A data center couples together large numbers of servers and multiple storage apparatuses using a Fibre Channel (FC) interface. For example, drops in apparatus performance, the end of an apparatus' service life, insufficient apparatus capacity, a dearth of network bandwidth, and system expansion will result in a data center replacing a server, network apparatus or storage apparatus with a new apparatus, adding a new apparatus, or removing an old apparatus from the computer system.
With conventional server virtualization technology, multiple virtual machines can be operated in accordance with running virtualization software on a physical server. This server virtualization technology makes it possible to temporarily suspend a virtual machine that is running on one physical server and migrate this virtual machine to the virtualization software running on another physical server. Management tasks related to the addition, replacement and removal of a server are carried out using this technology.
As described above, in the prior art, it is possible to run multiple virtual machines on a physical server. To operate a virtual machine that is running on one physical server on another physical server, it is preferable that is also be possible to virtualize Fibre Channel ports and to migrate these FC ports in virtual machine units.
Accordingly, technology (NPIV: N_Port Identifier Virtualization) for virtualizing the name of an FC node port (N_Port), which is an FC protocol expansion technique, is used. FC ports can be migrated in virtual machine units in accordance with using switches and host bus adapters (HBA) that support NPIV.
In NPIV, it is preferable that a name identifier (WWPN: World Wide Port Name), which is given to a virtual node port (VN_Port), not be changed between the pre-migration server WWPN and the post-migration server WWPN. The reason for this will be explained. A zoning function, which is an FC switch security function, provides access control by using either the WWPN, which is the N_Port name identifier, or a N_Port ID. The N_Port ID is computed from a FC switch domain number or a physical port number.
A SAN (Storage Area Network) administrator, who differs from a server administrator, is the one who configures zoning. Therefore, changing the SAN zoning configuration in synch with server migration is a big job because different administrators must exchange information with one another.
In addition, there are two types of FC zoning. One is zoning based on the port identifier (N_Port ID). The other is zoning based on the name identifier (WWPN). In the case of the zoning based on the port identifier (N_Port ID), migrating a virtual machine always requires a zoning change. The reason for this is because the N_Port ID changes when the virtual machine is migrated to another physical server. Therefore, the transfer of frames related to the post-migration virtual machine is nullified by the zoning function based on the FC switch port identifier.
Therefore, in a case where a virtual machine is migrated between physical servers, it is generally necessary for the user, who administers the computer system, to configure the FC port zoning function on the basis of the name identifier (WWPN). The user has the VN_Port (the virtual N_Port of the NPIV) take over a WWPN that is the same as the pre-migration WWPN before and after the migration of the virtual machine. In accordance with this, the user is able to migrate a virtual machine to a different physical server without changing the FC switch WWPN-based zoning configuration at all (Non Patent Literature 1).
Most network equipment is configured redundantly. In a redundantly configured network, after replacing a piece of network equipment (a FC switch or the like) in the one system with a new piece of network equipment, the piece of network equipment in the other system can also be replaced with the new piece of network equipment. This makes it possible to achieve a higher performance and/or higher bandwidth network.
The addition of a storage apparatus or a migration operation in a storage apparatus will be considered. In a case where there is a function for the N_Port of a migration-destination storage apparatus to take over the WWPN of the migration-source storage apparatus, the user may be able to carry out a migration from the migration-source storage apparatus to the migration-destination storage apparatus without changing the zoning configuration of the FC switch.
However, in a first prior art, only control for migrating all of the volumes that belong to the virtual N-Port of the migration source is disclosed (Patent Literature 1 and Patent Literature 2). In the first prior art, no method is disclosed for migrating only a portion of the multiple volumes belonging to either a single physical or virtual N_Port to either an arbitrary physical or virtual N_Port of the migration-destination storage apparatus. Similarly, in a third prior art, only control for migrating one volume belonging to the migration-source virtual N_Port is disclosed (Patent Literature 3).
However, in a conventional FC, all the domain switches belonging to a fabric must provide distributed services possessing the routing information and the zoning information of the entire FC Fabric. In accordance with this, when there is an increase in the number of domains belonging to the fabric, the distributed services must communicate and exchange information with each other. Therefore, there is a limit on the number of domain switches that can be disposed in a single fabric.
Accordingly, expanded standards for the FCoE (Fibre Channel over Ethernet, Non Patent Literature 2) have been proposed (Non Patent Literature 3 and Non Patent Literature 4). In an extended protocol, only one Primary FCF (FCoE Forwarder) is disposed inside a virtual domain (Virtual Domain), and distributed services are handled by the FCF. In addition, in an extended protocol, multiple FDF (FCoE Data Forwarder) are arranged inside the virtual domain. Each FDF is equipped with only a FC routing data transfer mechanism. The scalability of the number of ports of a single domain switch increases virtually in accordance with using a single FCF and multiple FDFs.
The number of virtual domain ports can be increased in accordance with the FDFs. The number of domain switches constitutes only one Control FCF, which controls the FDFs. The number of domains belonging to the fabric does not increase. The Control FCF distributes routing information to each FDF. Therefore, each FDF is able to carry out routing inside the FDF, and to communicate directly with the other FDFs that belong to the same virtual domain.
The FC fabric zoning configuration is granular access control to the FC port. The FC zoning configuration is also necessary for curbing the propagation range of the RSCN (Register State Change Notification), which is an FC topology change notification. The reason for this will be explained below. When the FC port receives the RSCN from the fabric, the FC port must query the state of the fabric once again. For this reason, server I/O is temporarily interrupted. When expanding the propagation range of the RSCN, the range of suspended server I/Os will expand, making it necessary to curb the propagation range using zoning.
LU granular access control is not possible with zoning since access control is in FC port units. Generally speaking, in a case where multiple LUs are associated with a single FC port in a storage apparatus, an LU that is accessed by a certain server can also be accessed by another server. Accordingly, an LU granular security configuration is required. A host group configuration is a task for mapping a logical volume number (LUN: Logical Unit Number) inside a storage apparatus to a host logical volume number (H-LUN: Host LUN) that can only be seen by an identified host (Patent Literature 4).
Accordingly, a TDZ (Target Driven Zoning) protocol has been proposed in recent years (Non Patent Literature 5 and Non Patent Literature 6). In the TDZ protocol, the storage apparatus port configures zoning in the fabric. Since this enables the user to carry out the zoning configuration when configuring the storage apparatus as well, the number of FC fabric management processes is reduced.